1. Field of the Invention
The present invention generally relates to an image scanner, and more particularly, to a handy type image scanner for optically reading information such as characters and patterns displayed on an original by moving a case of the image scanner with respect to the fixed original.
2. Description of the Related Art
To display information data of information sources (originals) illustrating characters and patterns, as CRT (cathode-ray tube) images and hard copies, an image scanner has been widely utilized as an information input source. Depending upon the scanning methods, the image scanners are categorized into the following two modes. In the first mode, the information of the original is optically scanned by the image scanner while moving the original over the fixed image scanner. In the second mode, the information of the original is optically scanned by the image scanner while moving the image scanner over the fixed original.
In the conventional image scanner moving mode, one portion corresponding to the image scanner has been integrally formed with the other portion for processing the information input by the image scanner. Very recently, the image scanner is separately provided with the input data processing device. Thus, a handy type image scanner has been proposed which is manually movable on an original. Since such a handy type image scanner has various advantages in that an easy operable image scanner can be realized and only a portion of an original can be scanned which is required to be input, it may be widely utilized as an image scanner.
To input information of an original by employing a handy type image scanner, it is required to visually recognize a relative position between the original and the image scanner in order that the desirable information displayed position of the original does not depart from the readable range. Particularly, in a handy type image scanner, most of the input information data are constructed of a portion of the original, and moreover, the scanning direction of the image scanner may become unstable because the image scanner is manually scanned over the original. As a result, an excessive attention is required to a scanner operator, and the desired information of the original is not sometimes correctly input into the image scanner. In other words, if the recognition can be made in real time whether or not the desirable information of the original is located within the readable range, both the reliability and operability may be considerably improved particularly in the handy type image scanners.